Leases (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2022		Jun. 30, 2021		Jun. 30, 2022		Jun. 30, 2021		Dec. 31, 2021
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 14	[1]	$ 14	[1]	$ 29	[2]	$ 28	[2]
Lessee, Operating Lease, Liability, to be Paid	575				575
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(126)				(126)
Operating Lease, Liability	449				449
Operating Lease, Liability, Current	(30)				(30)				$ (30)
Operating lease liabilities	419				419				$ 434
PPAs
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	13		13		26		26
Lessee, Operating Lease, Liability, to be Paid	520				520
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(111)				(111)
Operating Lease, Liability	409				409
Property, Plant and Equipment, Other Types
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	1	[3]	$ 1	[3]	3	[4]	$ 2	[4]
Lessee, Operating Lease, Liability, to be Paid	55				55
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(15)				(15)
Operating Lease, Liability	$ 40				$ 40

[1] PPA capacity payments are included in electric fuel and purchased power on the statements of income. Expense for other operating leases is included in operating and maintenance expense and electric fuel and purchased power.

[2] PPA capacity payments are included in electric fuel and purchased power on the statements of income. Expense for other operating leases is included in operating and maintenance expense and electric fuel and purchased power.

[3] Includes immaterial short-term lease expense for 2022 and 2021.

[4] Includes immaterial short-term lease expense for 2022 and 2021.